Wolves, polar bears, and lions are some of Earth’s many hypercarnivores —meaning that meat makes up more than 70 percent of their diets.
But tens of millions of years ago, mammals that mostly subsisted on flesh didn’t exist.
It took considerable time for mammals to evolve the right teeth and digestive systems to become hypercarnivores.
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The remains of an ancient cat-like creature, described March 15 in the journal PeerJ, could help piece together the evolution of this class of predators.
San Diego Natural History Museum
Diegoaelurus vanvalkenburghae, roughly the size of a bobcat,isa newly-known species described from a well-preserved fossil of its jaw and teeth.
It’s part of a class of predatory mammals known as machaeroidines, which sported pointy teeth and lived up to 54.9 million years ago during the Eocene epoch.
Diegoaelurus went extinct 40 million years before the fearsome smilodon, or saber-tooth tiger, began to stalk prey through Earth’s forests and grasslands.
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Here’s a comparison between the smilodon (skull in background) and Diegoaelurus’ jaw. The latterwas much smaller and had a more pronounced chin bone.
San Diego Natural History Museum
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Machaeroidines were the first cat-like predators known to exist.
But their remains are limited to only a few isolated fossils, with Diegoaelurus adding to the bunch.
This map shows the distribution of machaeroidines in North America.
Diegoaelurus shows that machaeroidines were more diverse than previously realized.
San Diego Natural History Museum
“We already knew there was a large form, Apataelurus, which lived in eastern Utah. Now we have this smaller form, and it lived at approximately the same time.”
Diegoaelurus’s discovery raises the possibility that there are still more machaeroidine fossils left to uncover — and a whole lot more to learn about the evolution of the elusive meat-eating machaeroidines.